This will make a fake .xls (really a tab delimited file, but Excel will handle it just fine) based on the contents of *.files. You can specify multiple files or whatever (it's all handled by the -n option) if you want.
It is possible to write out a proper Excel file, but you'll need to install a separate module.
Code:
perl -n -e 'push @a, $1 if /pattern(capture stuff)/; END { print join("\t", @a)."\n"; }' *.files > foo.xls